Automatic control for nailing machines



April 5, 1938. H. PAXTON 2,113,530

AUTOMATIC CONTROL FOR NAILING MACHINES Filed Dec. 28, 1956 FIG. 1. w 75 ATTORNEY.

Patented Apr. 5, 1938 UNITED sTATlazs PATENT OFFICEy AUTOMATIC CONTROL FOR NAILING MACHINES poration of Delaware Application December 28, 1936, Serial No. 117,724

2 Claims.

This invention relates to safety devices and has particular utility in nailing machines.`

In nailing machines for making boxes automatically the component parts of a woodenA box 5 are fed from suitable magazines by various feeding mechanisms into the proper relation to be nailed together to form a box and are there suitably assembled by a nailing mechanism nailing the sides and the bottom of the box to the ends thereof. In such an automatic machine all of the mechanisms contributing to the assembling of the box are operated coordinately from one source of power. In the past it has been customary in operating these automatic machines to control their stopping and starting with a clutch. Owing to box parts occasionally being warped and jamming one or more of the feeding mechanisms, it has been necessary for the operator of the machine to run it With one hand on the clutch lever so that he could stop the machine immediately upon observing the malfunctioning of any mechanism therein.

As these automatic machines produce boxes at a rate of over four hundred and fty an hour the strain on the operator of having to watch each operation of the machine to see that it was performed correctly was a considerable handicap in continuous operation of these machines. Furthermore, it was almost impossible for the operator to notice that things were going wrong until the diiiculty had proceeded to such a point that a box was improperly nailed together in the machine, thus making it necessary to remove this box from the machine and rebuild it by hand. In other cases the delay necessarily incident to observing the malfunctioning of certain mechanisms in the machine would result in box parts becoming jammed in the machne so tightly that the operation of the machine would have to be interrupted for a long period while removing the damaged box material and resetting the machine for automatic operation.

It is an object of this invention to prevent malformation of boxes or the serious jamming of box 4.5 material in an automatic box making machine.

One of the principal causes of jamming in automatic box making machines is the locking together of adjacent box ends by virtue of the fact that these adjacent pieces have been sawed from Y 50 a log at the mill without changing the relative position of the material in these pieces as it existed in the log. This circumstance often resuits in such adjacent vpieces having a common knot hole extending through the two pieces.

55 Sometimes a section of the knot becomes loose in such a knot hole and keys the two pieces of shook together. Thus when the machine undertakes to feed one of these pieces of shook from the magazine it is locked to a piece next thereto which is disposed back in the magazine and thus prevents the foremost piece from responding to the feeding mechanism. v

One way this situation was formerly taken care of was to form a portion of the feeding mechanism feeding these box ends of such light ma- 10 terial that it would break in case of jamming from the cause just described. The first evidence that the operator would have if he was alert would be the failure of one of the box ends to be fed into the machine at the commencement of a 15 box assembling cycle. If the operator failed to notice this omission immediately the manufacture of an incomplete box was started before the clutch could be thrown out and the machcine stopped. Before the machine could again be started themissing box end would have to be supplied to the assembling mechanism and the broken feed device would have to be replaced.

It is another object of this invention to not only eliminate the necessity of the operator having to constantly observe the operation of the 25 mechanism feeding box ends in an automatic box making machine but also to eliminate the breaking of the mechanism feeding these ends and the starting of incomplete boxes by failure of such mechanism to feed an end when required.

The manner of accomplishing the foregoing objects, as Well as further objects and advantages, will be made manifest in the following description taken in connection with the accompanying drawing, in which:

Fig. 1 is a fragmentary side elevational view of the box end feed mechanism on one side of the automatic box making machine shown in U. S. Letters Patent No. 1,844,333 issued to Elmer C. Northrup on February 9, 1932, said view showing said box end feed mechanism with the present invention embodied therewith.

Fig. 2 is a plan view of the feed mechanism shown in Fig. 1.

Fig. 3 is a cross sectional view taken on the line 3 3 of Fig. 2.

Fig. 4 is an enlarged fragmentary cross sectional view taken on the line 4-4 of Fig. 3.

As the particular mechanism shown in the drawing for feeding box ends into an automatic box making machine is, with the exception of the new parts therein embodying the present invention, shown and described in the aforesaid Northrup patent, the disclosure in the Northrup patent will, to simplify the present specification, be embodied therewith by reference.

For convenience the letter E will be used to designate said box end feeding mechanism and the letter N to designate the nailing machine with which this feeding mechanism is embodied. Attention will rst be directedto the old parts of the mechanism E by use of the same reference characters by which these parts are identified in the aforesaid patent. mechanism E is supported on frame 2 of the nailing machine N and carries a stack of box ends 6 which individually are disposed vertically, the stack itself being echeloned by the fact that it is supported in a downwardly sloping hopper 1.

The box ends 6 are adapted to be fed forwardly one at a time by a lug 14 which is pivotally supported on a vertical axis on a horizontally reciprocating carriage Il, the movement of which is imparted thereto by an arm I2 connected with the power mechanism of the machine N. The carriage in each of its horizontal reciprocations feeds slats into the machine for forming one of the sides or the bottom of the box being assembled in the nailing machine N, but only one set of box ends 6 is required during all three of these side and bottom assembling operations. It is necessary, therefore, for the carriage to make three horizontal reciprocations and feed a set of box ends 6 into the assembling apparatus of the nailing machine N only during the first of each such group of three reciprocations.

To prevent the feeding of box ends 6 excepting during the first of each group of three slat feeding reciprocations by the carriage I I, the box end hopper 1 is provided with a forward plate 1a which guides the box ends 6 as they slide downwardly in the hopper 1 toward the lug 14 so that the rear edges of the ends 6 are disposed to the rear of the forward edge of the lug 14 when the carriage I I is in its rearwardmost position. This relationship between the box ends 6v and the lug 14 effectively prevents the feeding of a box end from the` hopper 1 excepting when the foremost box end 6 is fed forwardly a sufficient distance so that its rear edge is in advance of the front edge of the lug 14 thereby permitting the latter to be swung by its spring 14a behind the foremost box en d 6 so that upon the next forward movelment of the carriagevII the lug 14 thereon will feed this foremost box end 6 into the assembling mechanism of the machine N.

To accomplish this initial feeding movement of the foremost of the box ends 6 so that one of these box ends is fed forwardly lby each third forward movement of the' carriage II, a lever 15 is pivotally mounted on the frame 2 and this lever is moved by a cam arm 16 on a shaft 11. which is rotated by a chain 18 one revolution for each three reciprocations of the carriage I I. The rotating of the shaft 11 is so timed by the manner in which the chain 18 is connected to the power mechanism of the nailingmachine N that a box end 6 is fed forwardly into its dotted line position 6a just in time to be caught by the lug 14 as the carriage starts forward to feed the side slats into the machine for forming the first side of a box.

The parts described hereinabove are old in the aforementioned Northrup patent, the addition to the art provided by the present invention being described as follows. Chain 18 is connected to the shaft 11 through a sprocket |30 with which is embodied a torque clutch |3|. This torquev lclutch includes a base |32 on which the sprocket Thus it is seen that the |30 is mounted for idle rotation. The clutch |3| also includes a sleeve |33 which surrounds the clutch base |32 and is integral with the sprocket |30. Sleeve |33 has a tube |34 extending radially therefrom this tube having a cap |35 through which a plunger |36 extends. The plunger |36 has a head|31 on its inner end and a nut |38 on itsouter end and a spring |39 is coiled about the plunger |36 between the cap |35 and the head |31. Provided in the clutch base |32 is a recess |40 into which a steel ball |4| is continually urged by contact of the head |31 with this ball under pressure of the spring |39.

Being integral with the sprocket |30, the sleeve |33 and other parts mounted thereon rotate with the Sprocket |30 as long as the power mechanism of the nailing machine N to which the chain 18 is connected, continues to function. This power mechanism is run by an electric motor (not shown) the circuit of which, in this invention, includes a switch |50 which is adapted to be acuated by a control arm |5I, the latter being connected by a link ,|52 to a cam arm |53, the other end of the latter arm being pivoted at |54 to the frame 2. The cam arm |53 has a curved portion, |55 the. curvature of which is formed about the axis of the shaft 11 with a radius just slightly longer than that at which the outer extremity of the plunger |36 normally revolves.

When the box making machine N is operated to make a box the box ends 6 are advanced one at a time by the lever 15 so as to be fed forwardly by the carriage I with each set of slats for forming the first side to be assembled with the box. In case the foremost of the box ends 6 in the magazine 1 were for some reason to jam, as would be the case if they were keyed together by a loose knot in a common knot hole, there would be such a resistance setup to the forward movement of the lever arm 15 by the cam 16 that the torque clutch base |32 would be held still with the shaft 11 and the steel ball |4I would be forced from the recess |40 by the increased torque set up between the sleeve |33 and the clutch base |32.

The angular relation of the clutch tube |34 to the cam arm 16 when the ball I4| is located in recess |40 is as illustrated by the full line positions of these elements in Figs. 1 and 3. In the event of the jamming of the Vforemost box end 6 in the magazine 1 and the dislodging of the ball |4I from the recess |40, a radial outward movement of this ball would result which pushes the plunger |36 outwardly, as shown in its dotted line position |10 in Fig. 3. Although still rotating with the sprocket wheel |30 the plunger |36 is, by its outward movement, caused to lift cam arm |53 thereby swinging the switch arm |5| from its full line position in Figs. 1 and 3 to its broken line position in Fig. 3 which opens the switch |50 and stops the power mechanism which drives the nailing machine N. Thus the entire machine is stopped automatically and without the intervention of the operator and without there being any necessity for his even observing the jamming of the box ends 6.

The stopping of the machine of course immediately calls itself to the operators attention. When upon examination he discovers the source of the trouble it is only necessary to lift the jammed box ends 6 from the hopper 1, reset the clutch |3| by seizing thecam arm 16 and rotating this into the position which it would have had if the jamming had not occurred and then immediately start the machine to continue with the manufacture of boxes. It is thus seen that a resumption of full automatic operation of the nailing machine N after being interrupted by a jamming of the box ends when this machine is equipped with my invention is an extremely simple and short process compared with the arduous repairs formerly needed before operations could be resumed.

It is also apparent that when the nailing machine N is equipped with my invention the need for the operator constantly observing the functioning of the two box end feed devices E on the machine is done away with as with my invention the operator may depend upon it that Whenever any jamming of these box ends occurs it will be called to his attention immediately by the Stopping of the machine.

While the drawing of this application does not show the entire Northrup machine, it is to be understood, as previously mentioned, that the Northrup patent disclosure is included by reference in the disclosure of this application. It is also to be understood that the scope of this invention is not to be considered as limited to the specific embodiment illustrated herein, as the safety device of my invention is not only applicable to a mechanism for feeding box ends into an automatic box making machine, but is also applicable to the feeding of the slats into such machine for forming the sides and bottom, of the box. It is further applicable to the controlling of individual mechanisms in various machines in which a plurality of mechanisms is operated by a unitary power means for cooperatively achieving a single result.

One of the particular advantages of this invention is that the individual mechanism is protected from being damaged by the power means of the machine, when the individual mechanism jams, by the severing of the drive connection with this mechanism and at the same time the destructive operation of the other mechanisms in the machine, while the jammed mechanism is stopped, is prevented by the automatic stopping of the unitary power means, which in this case is the motor driving the machine.

What I claim is:

1. In a box nailing machine, the combination of: means for transmitting an initial feeding movement to a box part to start the feeding of Said part into proper relation for assembly with other box parts; power means for actuating said feeding means; a torque clutch connecting said feeding means and said power means, said clutch being automatically disengaged when thetorque required for the operation of said feeding means rises above a given value; and means for stopping the operation of said machine, said means being responsive to the throwing out of said torque clutch to stop said machine.

2. In a box nailing machine, the combination of: power means for operating said machine; means for transmitting an initial feeding movement to a box part to start the feeding of said part into proper relation for assembly with other box parts, said means including a shaft, a torque clutch mounted on said shaft and said power means, said torque clutch automatically opening to disconnect said power means from said shaft when the torque transmitted through said clutch rises above a given value; means for stopping the operation of said power means; and means actuated by said power means and responsive to the opening of said clutch to actuate said means for stopping the operation of said machine.

HALE PAX'ION. 

